


Pent Up Beasts and Where To Find Them

by YinYangGangBang (YinYangBangBang)



Category: RWBY
Genre: Beast Blake, Beast Form, Bulges, Come Inflation, F/F, Future AU, Inflation, Knotting, Plot What Plot/Porn Without Plot, Roleplay, Shameless Smut, Size Difference, Size Kink, Totally shameless and the lord is looking down on me and shaking his head, belly bulge, forgive me father I aint going to heaven now
Language: English
Status: Completed
Published: 2017-10-10
Updated: 2017-10-10
Packaged: 2019-01-15 19:27:34
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,467
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12327333
Author URL: https://archiveofourown.org/users/YinYangBangBang/pseuds/YinYangGangBang
Summary: Ruby arrives back from her field mission, eager to rush home and make love to her girlfriend. But she's in for far more than what she bargained for when she meets Blake's beastial form for the first time.





	Pent Up Beasts and Where To Find Them

**Author's Note:**

> Extremely shameless self-satisfying roleplay edited into a fic between Mattiams and I. This is... a lot more intense than anything I'd write solo so I'm afraid I can't promise much more of it. But I hope you enjoy it regardless!

Ruby sighed with relief as she turned the key to unlock the door to her and her partner's home. She'd been away for a week doing various missions out in the wilderness, with very little company other than the Grimm she had to fight every now and again. No time for rest, no time to relax. Now, she was looking forward to an evening with Blake, with all the cuddles and relaxation they could get. She was certainly hoping Blake would be in the mood for 'relaxing'.

"I'm home!" Ruby called out as soon as she opened the door, closing it behind her. "God I'm so glad to be back! Did you miss-"

But Ruby didn't expect the sight she'd see upon arriving home. She'd heard of particular beasts that crawled in the night, more formidable than Grimm if provoked. Most thought they were a myth, but Blake had told Ruby they were very real, and that she was one of them. But this was the very first time she'd see that form of her girlfriend. Perhaps she didn't expect Ruby to be home so early...

Laid on the sofa was her large, black panther form. It was much larger than average and hosted sleek black fur alongside bright yellow eyes. She was fully stretched out, having felt pent up as of late keeping the beast form from Ruby for so long. She'd been wanting to show her, after all, she was her girlfriend! But the mission Ruby took was very specific and lasted days, and was only suited to Ruby on her own. Other than that, there had been no good time to show her. So imagine her surprise when Ruby walked through the door at that moment.

"... Me?" Ruby finally finished her sentence.

While Blake had given her a description previously, she'd never expected her to be as big as she was. If she stood on her hind legs she'd probably be too tall for the room! And Ruby didn't even dare try to imagine how small she'd look next to her. More to stop herself getting flustered rather than any fear.

"So... this is 'the beast'?" Ruby asked, eyes gazing down her form. For a moment she did stare at the down below, somewhat amused that the fur managed to hide  _ the package _ very easily in this form, but quickly looked back up, hoping Blake didn't notice. "I-It's... um... wow."

Blake, even with the fur, blushed as bright as the sun, looking away shyly before her ears flicked and she looked to Ruby again. Opening her mouth and showing off her impressive teeth,

"Ru-b-Y."

She struggled, she wasn't supposed to talk in this form. But she wanted to reassure Ruby, despite the fact that she was okay with it. Perhaps it was to reassure herself? She noticed the lingering look from Ruby down below and blushed even more, laying on the floor and covering her eyes with her large paws.

"You're so... furry?" Ruby didn't know what to say. Perhaps 'big' would have given off the wrong impression, so she didn't say that for now. Instead, she took a gentle step closer, taking off her backpack and crescent rose and leaving them back behind the door. While Blake appeared to be blushing, she needed to be cautious. After all, while she might not be scared by this form and while she knew it was her girlfriend deep down, they needed to be careful for both their sakes. Both didn't quite know what she was capable of. "Sorry, I just... I've never seen this before. You can hear me and you're thinking as normal, right?"

Instead of answering she gave a small purr and nodded her head, noticing her loves small step, so she mimicked the same, taking a small step forward, which was for all intents and purposes was a stride due to her size. She cocked her head to the side.

Furry? That's what she had used to describe her? Not big or terrifying? Her Rose was so sweet to her. She took another step, and cautiously pushed her snout against Ruby's hand as if asking for fusses.

Perhaps Blake in this form was just a lot more forward about what she wanted. If these beasts were supposedly Grimm hunters they'd need to be, after all, you'd need the instinct to attack first without hesitation. Ruby was used to Blake regularly being more reserved, leaving any petting for their snuggle sessions much later in the evening. But she could never ever resist them. Despite how different she looked, it was still her Blake.

Right away she ran her hand through the now thick fur atop her head, gently scratching at both her scalp and at the bottoms of her ears. More space to work with, but she tried to scratch as she knew her girlfriend loved it, even sparing a reassuring smile. "You really did miss me, huh? Maybe we should snuggle on the sofa? I-if you can fit on it."

Blake purred even more deeply at the fuss she received, moving her head so Ruby's scratching fingers hit the spots she could never reach in the form. Her tail, thick and heavy swayed, displaying her happiness. She then pulled away when Ruby suggested the sofa, or the nest as she knew it, they sometimes slept on it more regularly than the bed.

But a moment later she approached it and proved she was too big for it. Giving a small whine to Ruby.

"Awh..." Ruby shared in her disappointment, but not wanting to dwell on it, her hands quickly went back into Blake's fur again, scratching a little firmer this time, particularly under her chin. That always seemed to be a good spot with most creatures she encountered, so why not her too. "That's ok! We can just... lay down here and get a bigger sofa another time, so we won't have this problem again."

There was a good twist to Blake being so big, perhaps if she was comfortable with it, Ruby could simply rest on her. It didn't matter as long as she spent time with her, doing whatever Blake wanted. Which right now seemed to just be petting.

Perhaps it was a shame she wouldn't get to 'relax' with her tonight, but that could wait. Still... the idea had been in her head most of the journey home. It was all she could think about, coming home to her lover, going straight up to bed and releasing all that pent-up tension in the throws of pleasure. Another night maybe.

But the beastly Blake's senses were improved vastly. She’d definitely pick up on that.

Blake was like a puddle in Ruby's hands, purred and slumping on the floor happily as Ruby fussed her. The beast only coming back to reality when she took in a breath through her nose, picking up all the soft scents of the apartment, and a new and sharp scent. She... She had smelt this before. When she and Ruby 'snuggled' when she was in her human shape.

Ruby was... Aroused?

Her mind raced. Maybe she had simply been anticipating their snuggles tonight, or maybe this was a result of what she had glanced earlier? Cocking her head to the side she rolled slightly, exposing her package to Ruby, the tool throbbing softly as it slowly began to grow.

At first, Ruby hadn't noticed. She was too focused on scratching the skin under all that thick fur, assuming the shifting of movement was just because she was enjoying it and craving more.

_ 'Where else was it some things liked to be scratched?' _ She thought.  _ 'Oh yeah! The belly! ' _ As she began to scratch her way down, only then did she finally look in that direction... and then freeze up.

As she watched Blake more obviously display herself, she noticed the package starting to throb and grow.  _ 'Holy fucking shit.' _ She thought again, a clear blush forming on her cheeks.  _ 'She's huge... And that's not even full yet.' _

That thought alone was making her utterly red, and down below utterly wet. The burning sensation she began to feel on the way home was returning at double the force, something a beast such as Blake easily picked up.

Oh. Oh, she liked that. Ruby was so easy to turn on. And it seemed even easier in this shape. She gave a low grumble, letting out a breath as it continued to throb and grow to what her beastly mind comprehended at half mast. The smell coming from Ruby was maddening. This was unbelievable! How could she smell so good!

From her position, she wiggled, and a moment later had her nose up Ruby's skirt, her long thick tongue running up and against Ruby's covered sex.

"W-woah!"

Poor Ruby was caught by surprise! She'd been so ridiculously focused on the hardening length down below she hadn't noticed Blake's head get so close to her. "W-Wait! Is this safe? C-can you... you even..."

_ Oh god, that felt amazing. _

Ruby hadn't even got her tights or underwear off yet, but that tongue was so long and big it didn't matter. Was it even right to be thinking of such raunchy thoughts of Blake's beastly form? Then again, as she reassured herself many times already; it was still her girlfriend.

Letting a moan escape her lips as she looked down at Blake's head down there, she then looked back toward the hardening shaft. Annoyingly Blake was now so tall she couldn't even offer a hand to get it to full length, not that she even knew how big full length would be anymore. Regardless, she wanted to be sure they were on the right page.

“You… want me to get naked?”

Blake gave another purr and another lick for good measure. Nodding her head and pulling away from Ruby with the beastly equivalent of a grin. Her cock throbbing with her heartbeat, and now nearly at full mast.

The bigger said cock got, the more intimidated Ruby was. Not only were there small, ribbed barbs down its length, but the way it was shaped at the bottom was very clearly a knot, one that would probably get huge when things went that far.

**IF!** If was the right word. Blake for now just wanted to use her tongue, and she was more than satisfied with that! Maybe Blake was doing is because she knew it wouldn't work? Maybe it was safe after all?

They could worry about that later after she'd have the best tongueing in her life. As she finished stripping off her clothing and tossing it all to one side, she returned to Blake's head again, already breathing heavily in anticipation. And she positioned herself above her head and got to her knees to sit on her face.

Blake didn't even care about her own sex at this point. Ruby clearly wanted to be eaten out and with her long tongue, she would do just that. She started off slow, the rough tongue dragging up against her roses lips, wiggling like a snake before getting to her clit and dancing, trying to coax it out. Then just when it did she let her tongue dive in and wiggle about, filling her lover like her cock usually would in human form.

When she pulled away a variety of tastes littered her tongue, the beast happily purring before attending to her clit once more.

Ruby was in pure bliss. She had the best of both worlds all in one skilled mouth! That tongue was not only making her clit tingle with pleasure and her body quiver with joy but when it went inside, it was just as firm and long as Blake’s regular member. But a tongue was far more flexible. She couldn't help when she grasped a handful of Blake's fur with each hand, grinding herself up against her mouth even more.

God, it had only been a few seconds, but already she was so  _ so _ close! Blake took it that her partner very much enjoyed that, and so continued, changing it up every few moments to take her off guard and get her closer and closer to orgasm. Besides, the way she clung onto her hair made her shiver in delight.

But she was missing out, her cock was at full length now. Definitely over ten inches long, if not more and with a thick girth to measure. It was like something from pure fantasy.

Finally, after a few seconds longer, Ruby was done. It was definitely one of the bigger orgasms Blake had ever seen the girl go through, judging by how she grasped at Blake's fur all throughout shuddering all over, swearing under her breath. Her muscles inside tightening against the writhing muscle inside her.

But it just wasn't good enough.

While this beastly Blake's tongue filled her around the same amount as her human form's cock did when they got at it, suddenly that didn't feel enough. It was probably because she was staring down at a cock far bigger than that throughout. The way it twitched slightly and the small drop of pre she could already see, Blake was rearing to go.

She didn’t know how to help that just yet. Taking a moment to regain her breath, she laughed gently, starting to get back up again off Blake’s face. "You can do that again some time. Jeez, that was insane."

Blake smacked her lips together and licked them, Ruby was always sweet and today was no exception. But that orgasm. That was the hardest she had seen her love shake! She closed her eyes for a moment as she felt her cock continue to throb, so hard now that it was painful as beads of pre dribbled down, coating the cock in lubricant.

She grunted again, the beast arching her back as the thick pre-made the journey down the length so thick that the cock bulged slightly.

"R-Rubb-les." She gasped, having her face in Ruby’s crotch for so long had made it impossible to think. She needed her own finish and needed it now.

Ruby looked down to the cock once again. It was still intimidating to look at, but it really was throbbing with need. Her poor Blake was just as pent-up as she was while she was away, she couldn't just leave her like that, no matter the form. But as she crawled closer toward it, the more she began to question;  _ Could it even fit? _ While the couple had debated on getting bigger toys this was definitely a stretch. It looked as though if she sat on it the thing would probably be ramming into her chest. But there was no one better to ask than Blake herself. So as she knelt by its side.

"Will it fit? Do I have to get it wet or something first? Sorry, I've just... I've never handled this before."

Blake whimpered at how close her lover was to her plight, grunting again when she asked about getting it wet. Blake seemed to be doing a good enough job of that herself with the pre dripping down, doing the job for Ruby. Blake tried to move it closer to Ruby, nodding gently.

"Yea... Fit." She managed to say. "M-make. It. F-f-fit."

Seeing that as the way to go, Ruby made an effort to spread that amount of liquid all over Blake's member, noticing with each stroke that she was producing more to aid in it. This was a relief, at least no matter what her girlfriend practically had her own supply of lube for them to use, and not to mention the tongue from earlier made Ruby plenty wet enough for this.

Once satisfied that the shaft and a small amount of the knot was covered, she looked to it again. She was  _ still _ nervous about the side, especially Blake's 'make it fit' comment. Ruby wasn't exactly a large person, this would probably be the biggest thing she could take. If she ever could. Here went nothing…

"Where do you want me? The floor with you on top? Or should I sit on your lap?"

"La-p."

Blake whimpered. She wanted to pound her lover into the ground if she was completely honest, but she knew she couldn't. She had to let Ruby get used to her size first before they went any further. When she was comfortable, then she would pound her into the ground. Maybe.

The beast licked her lips, she so wanted to lock herself inside Ruby and fill her. She had many times in human form, but the knot wasn't a thing in that shape. "G-get you... Used. It."

"Alright... ho boy." She repeated. This was really happening. At first, she just stood over the top of it, looking down at it as though it were some kind of weapon. It might as well be, with how big it was both in length and in girth, it looked like it could split her in two!

But she wanted it, she wanted it badly. Though she may not have admitted it to many, but being dominated by some kind of beast was definitely a fantasy of hers. Blake was about to make it come true. At least she was willing to let her take charge in order for her to get used to it.

Slowly she lowered herself, reaching for the cock to aim it just right. She could feel the ribbed barbs already in her hand, knowing they'd feel infinitely better once they were in and rubbing her all over. Gulping, she finally lined it up with her entrance…

"Fuck, this is big..."

She spoke very quietly, still not quite bringing herself to lower herself down even more onto it yet. But after a small breath in and out to calm herself down, she finally did and allowed a couple of inches to penetrate her. A tiny amount, but given the girth, she knew she'd need to take it slow. She had to stretch already to allow it in.

"Fffffffuck..."

If she was in human form and with opposable thumbs Blake would have held onto Ruby's lovely thighs or curled her fingers into the blankets. But she wasn't in human form. There were no blankets, the beast having her breath taken away as Ruby slowly let some of her length go inside. It was so warm and tight that she could barely comprehend it. She had taken Ruby countless times before, but this form was entirely different, and Ruby felt so different. And so good. Even with a few inches. Her tongue hung out and hungry amber eyes watched, eager to see her cock plug and fill Ruby.

"You... O-Kay?" She asked, slight concern in her eyes despite the desire the buck her hips upwards.

"J-juuust... fine...!"

Perhaps she wasn't, but she refused to give in. Blake needed her, and she was going to be the best she could for her no matter what! Sinking down three more inches, she let out a deep, satisfying moan.

This was about the length of Blake's usual penetration when she was human, but in this form because of the girth, something was different. She tried to look down at the cock below. The knot was getting bigger already, but Blake would need to thrust in order to get it to full size. But that wasn't all she noticed when she looked down.

Already there was a bulging in her belly, curved to the shape of Blake's massive cock. She stroked her hand over that bulge to confirm, and it seemed she was right. This really was like something out of her more kinky fantasies. It was an oddly humbling feeling, seeing such a strange fantasy being brought to life before her.

Blake let out a small moan at how Ruby handled her cock, her mind on the same track. When Ruby brushed over the bulge she couldn't be happier. She closed her maw and tried her best to stop herself from thrusting, she so wanted to just let loose, but she couldn’t! She needed to be still and be sure Ruby could handle it. "R-Ubbles. Feel good?"

Ruby didn't answer that until she sunk herself all the way down, moaning again as the bulge moved it's way up as she took more and more, already feeling her toes start to curl as she got used to it. But eventually, she was stopped sinking further by the bulbous growing knot. For now, she was as deep as possible.

"Holy shit..." Ruby was already breathing heavily, running her hand over the bulge again like she couldn't believe it was there. This thing would be pounding at her insides! Not that she cared so much anymore. That would feel good. She seemed to handle it so far, maybe if Blake did decide to thrust…

"S-so good! I-it feels… G-Gah… so full... hmmm..." The poor rose could barely string a sentence together anymore. Her mind was flooded with joy. All she could think of was the now, in this moment.

Blake was panting, her large chest rising and falling as Ruby finally got all of her length inside sans the knot. This was like heaven! And she hadn't even tried thrusting yet, using her tiny barbs to stimulate and tickle at Ruby's senses. Experimentally, she pushed up, bucking Ruby ever so slightly before she landed again, the pseudo-thrust meaning when Ruby slammed down again that she enjoyed all the benefits of Blake pounding her.

"Oooh!" Even just a few inches moving were such a huge sensation. Not just the member moved, but the bulge too, making the whole thing seem like they were doing so much more.

God, she was so filled! She tried to aid in what Blake was doing, pushing herself up and down to match with Blake's movements. It was at a snail's pace, but all she could handle at the moment. With each thrust she felt those barbs stimulating her inner walls, feel each and every rib touching her. God this was like the perfect sex toy by design.

Blake grunted, Ruby was really getting into the swing of things now and she knew she was more used to the size. A few moments later and her mind was made up, beginning to speed up her thrusts, making sure to meet Ruby's very own.

They continued in this fashion, both learning each other's bodies again as they both made love, both moaning and panting as they were brought closer and closer to a finish. Blake was so close now, but that thought went out of her mind when a sudden she'd thrust from both of them pushed her growing knot into Ruby with a  **POP** .

"AH!"

Ruby yelled out loudly. Her poor opening had been stretched enough with the girth of the length alone when Blake finally pushed the knot inside, she couldn't help her yelling. It was trapped. Ruby couldn't help but quiver as it sat inside her, the knot and length both filling her entirely. Making her stomach bulge even more.

She hadn't quite finished yet, but she was determined to make Blake do so. They'd come this far already she didn't want to quit now. So she very carefully tried to pull herself up and down against the knot, trying to stimulate her in that way. Ruby alone would never be able to pull it out, but she hoped in pulling up against it it would spur Blake to finally orgasm.

Suddenly without warning, Blake roared. Her cock gave a final throb, and the damn broke. She began to fire rope after sticky thick rope inside of Ruby's overly stuffed sex, stuffing it even more and slowly filling her as she laid her seed inside, the beast grumbling happily as she did so.

Usually when that happened Ruby couldn't feel it too much, just a small indication that Blake was finished. But this form? Everything was so much more.

Perhaps she'd overestimated what she could take but she felt Blake filling her up, finding herself squealing in surprise when she felt her belly getting bigger. To her surprise, it was a huge turn on. A mix of being filled and of the knot stuffing her up made her quiver, even more, toes curling and hands grabbing handfuls of fur once again as she came harder than she ever had before, tightening against Blake's entire cock. She could barely think straight anymore, but she knew that it was probably the best she's ever had in her life.

So far.

Blake was only just finishing up when she felt Ruby clinging on for dear life, her body shivering and shaking as she underwent another orgasm, watching as her belly filled with her seed, giving her an adorable pudgy look, like she'd eaten one too many cookies. The beast reached up and licked her lips as if begging for a kiss to reassure her that they were both fine.

Ruby was left panting and just quivering every now and again, she looked up to Blake's face again. She offered a reassuring smile, trying her best to lean forward to offer that kiss, but Blake was so tall she couldn't reach! Not with the knot still inside her, connecting her to her hips.

Leaning forward, she petted Blake's fur and gently kissed as far up as she could reach, just below her neck. With such a large member and so much of her lover's seed inside her, she didn't want to move much. She just wanted to enjoy this new, fantastic afterglow. "Hmm... hah... that was so good..."

Blake cocked her head to the side, she hadn't expected such a reaction from her Rose and it filled her with confidence. The large beast purring in satisfaction at Ruby's small movements and kisses. "Maybe... Mor-e Oft-en?" She purred, trying her best to kiss and lick Ruby too. She felt move movement, and felt her knot slowly but surely shrinking, she could pull out soon. 

Rubbing her rather full belly gently, she couldn't help but let out a small laugh, gradually adjusting her position on Blake's body so she could cuddle her comfortably. "Maybe... let's just make sure my tummy goes down again first, otherwise I'll be  _ too _ full..." With her spare hand, she gently ran through Blake's fur again, scratching under her chin where she could reach. "But you can definitely be in this form more often. We'll get bigger sofas and a bigger bed so you can sit on them in this form. This probably sounds silly, but I'd love to cuddle you and sleep by your side when you're this big and furry."

Blake purred affectionately. Now that was an arrangement she could certainly live with.


End file.
